Figure 11. Neurally evoked mechanical responses to EFS of gastric fundus muscles from P5 Ano1^+/+ control and an Ano1^−/− sibling.

Gastric fundus motor responses at the stage of development were small. A–D, motor responses to EFS (1 pulse and 5 Hz for 1 second; arrows and bars respectively) of an Ano1^+/+ gastric fundus. A, under control conditions with no drugs added, neural responses at this developmental age were predominantly excitatory. B, l‐NNA (100 μm) increased the amplitude of EFS evoked contractions at all frequencies tested. C, addition of neostigmine (1 μm) in the presence of l‐NNA produced a marked increase in the nerve evoked contractile responses at all frequencies tested. D, in the continued presence of l‐NNA and neostigmine, atropine (1 μm) abolished EFS evoked contractions. E–H, motor responses to EFS of a P5 Ano1^−/− gastric fundus. E, little or no contractile responses were observed under control conditions. F, l‐NNA (100 μm) did not reveal excitatory contractile responses. G, in the continued presence of l‐NNA, after the addition of neostigmine (1 μm), EFS evoked contractile responses markedly increased in amplitude and these were similar to Ano1^+/+ tissues. H, atropine (1 μm) in the presence of l‐NNA and neostigmine abolished EFS evoked contractions. I–L, summary of EFS evoked responses of a P5 Ano1^+/+ (white bars; n = 8) and Ano1^−/− mutants (black bars; n = 15). I, under control conditions (no drugs), Ano1^−/− fundus responses were reduced compared to Ano1^+/+ controls but not statistically different. J, in l‐NNA, EFS evoked excitatory responses were significantly greater in Ano1^+/+ than Ano1^−/− mutants at most frequencies tested (^* P < 0.05, one‐way ANOVA). K, in l‐NNA, neostigmine markedly increased contractile responses that were not statistically different between Ano1^+/+ and Ano1^−/− animals. L, neurally evoked contractile responses were inhibited or greatly attenuated by atropine in both animal groups.